The field of the invention relates generally to bleed air systems, and more specifically, to a method and systems for an integrated ejector valve assembly for supplying bleed air to an aircraft.
At least some known aircraft use engine bleed air for cabin pressurization, anti-ice and other functions on the aircraft. The bleed air pressure must be reduced under most operating conditions to provide a regulated air supply. Engine bleed air pressures vary greatly with engine speed and operating altitude. Engines typically have two bleed extraction ports, a low pressure (LP) port which is used whenever possible and a high pressure (HP) port which is used only at conditions of high altitude and/or low engine speed when LP bleed pressure is insufficient to supply the needs of the aircraft.
An ejector can often be beneficial using some regulated HP bleed air to boost LP flow and extracting LP flow when the LP pressure is lower than required. A pressure regulating and shut-off valve controls the bleed air system pressure. An LP non-return valve (NRV) is usually provided to assure that there is no back flow from the HP bleed port to the LP bleed port. An HP pressure regulating and shut-off valve controls the flow of air from the HP bleed port when LP air pressure is insufficient.
A typical jet engine has two bleed air extraction ports, a low pressure (LP) bleed port and a high pressure (HP) bleed port. Engine efficiency is maximized by using LP air whenever the LP bleed port pressure is adequate. The HP bleed port is used to supply bleed air only when necessary. It is often advantageous to extract equal bleed air flows from each engine in both the LP and HP modes while controlling the bleed air system pressure.
Known bleed air systems include a pressure regulator downstream of the bleed ports that may also provide a shut-off function so they are known as pressure regulating shut-off valves (PRSOV). The LP NRV prevents backflow into the engine LP bleed port when the LP pressure is larger than required bleed system pressure. A high pressure shut-off valve (SOV) is opened when LP air pressure is insufficient. In some cases, this valve is also a pressure regulating valve (HPPRSOV).
The transition from LP to HP is typically abrupt. When the LP pressure is inadequate, the HP shut-off valve (SOV), or HPPRSOV in some cases, is opened. The higher pressure from the HP part closes an LP check valve to prevent backflow. The entire flow is then supplied by the HP bleed port. In some configurations, the LP NRV and LP check valve functions are performed by the same component.
However such systems include many components that each includes numerous parts. The individual parts must be stocked for maintenance and repair operations and the number of components adds to the weight of the aircraft, causing a loss of efficiency.